What does a Sinclair Spectrum Emulator have to do with anything? Mind you, the Z80 proc would be familiar territory, but being a Yank we never really saw any Sinclair models newer than the TS1K, which was just a Zed-Ex 81 with the RAM doubled, and usually sold for 30 bucks at the pharmacy.

Or did you mean something else? (that's the only thing I'm familiar with "QAOP" meaning)

Can't say I'm familiar with or come across that... was it specific to a certain platform? Sounds similar to the TRS-80 arrow key placements, which were a pain since you needed both hands for arrow leaving no hands free for anything else. Certainly not seen that one on any PC, TRS-80 or Commodore software. (Lemme guess, Apple?)

Most C64 software I ever dealt with was IJKM, didn't find out why until I wrote the '64 verions -- they're all on the same CIA port. WASD actually took two port reads.. QAOP would be four separate ports on CIA1. Similarly you did see WASZ on some C64 programs -- or even both WASZ and IJKM for multiplayer, as it too is on a single port read.